Kenaf is a plant of considerable potential, as yet mostly unfulfilled. It is native to central Africa and has been cultivated in Egypt for thousands of years as a source of fiber for making clothing, rugs, rope and other products, as well as for other uses. Kenaf grows to heights of 12-18 feet in a 150 day season and requires little or no pesticides or herbicides if it is grown in the right locale. Kenaf can produce 5-10 tons of dry fiber and core per acre. The plant has two distinct types of material: an outer fiber known as fiber, bast or bast fiber, comprising about one-third by weight of the plant, and a core. The core is a low density woody type material while the bast is a much lower density fluffy type fiber of high tensile strength. As harvested, the bast fibers tenaciously adhere to the core. In a typical harvested kenaf crop, the core is slightly tapered from bottom to top and has a small diameter at the top in the range of 1/4-1/2".
The core and fibers have distinctly different uses and must be separated before they are suitable for these different uses. The core is useable as animal bedding, oil-absorbent material for oil spill cleanup, animal bedding, potting soil, kitty litter and particle board or other similar construction materials.
The most promising high volume use of bast fibers is in paper manufacture. Another potential high volume use is in the manufacture of fiberboard used in automotive door panels and the like. The economics of bast fibers in these high volume situations are attractive because the cost of the cultivated crop compares very favorably to the cost of timber which is the conventional source of fiber used in paper and fiberboard production. The difficulty has been in separating the core from the bast fibers in large quantities. Many different attempts have been made, all heretofore futile, to separate kenaf core from fiber on an industrial scale.
The disclosure of a kenaf separator mounted on the back of a tractor is found in U.S. Pat. No. 2,755,511. Other disclosures of interest are found in U.S. Pat. Nos. 870,838; 1,797,507; 2,688,161; 2,817,119 and 4,974,293.